Pneumatic tire



1931- E. HIBBERT 1,829,433

PNEUMATIC TIRE Filed Oct. 24. 1929 Patented Oct. 27, 1931 UNITED STATES PATENT OFFICE ERNEST EIBBERT, 0F GOULBUR-N, NEW SOUTH WALES, AUSTRALIA, ASSIGNOR TO THE PIONEER CELL TYRE COMPANY LIMITED, OF SYDNEY, NEW SGUTI-I WALES,

AUSTRALIA, A CORPORATIGN 0E NEW SOUTH WALES PNEUMATIC TIRE Application filed October 24, 1929, Serial No.

This invention relates to a process for the manufacture of tubes for resilient pneumatic tires for the wheels of motor vehicles and the like and has for its principal object to provide a durable and eflicient inner tube which will practically eliminate punctures and blowouts. This invention comprises a series of steps in the process of manufacture of an inner tube and provides for the formation of air cells in the tread portion of the tube, the cells being adapted in conjunction with a ire cover to retain air at atmospheric pressure.

In order that the invention may be more clearly understood, reference will now be made to the accompanying drawings in which Figure 1 is a sectional view showing one form of tube made according to the invention the tube being disposed in a tire cover of ordinary construction.

Figure 2 is a sectional perspective View showing a portion of an improved tube made according to the present process.

Figure 3 illustrates an application of a modification of the process wherein a saddle shaped tube portion is constructed according to the present invention and is disposed round a separate pneumatic tube.

The invention will now be described by the aid of the drawings. The tube 0 is formed in lengths from laminated soft air holding tube rubber upon a suitable mandrel having a diameter less than the internal diameter of the tube when finished.

When the requisite number of laminations of air holding rubber have been built upon the core the latter is removed from the tube. The tube is then joined and inflated with air at a suitable pressure in order firstly, to enlarge the internal cavity of the tube until its internal cross sectional area isequal to the internal cross section area of the tire cover in which the finished tube is to be placed, and secondly to keep the so-far-built up tube (C) in shape.

The tube C is then further built up by being coated with junction rubber in solution or in sheet form. After the junction rubber has been applied to the tube the latter is bound with laminations E of sheet rubber,

402,277, and. in Australia November 1, 1928.

which is preferably of a kind known as carbon black mixed stock. A strip of tough tread rubber (B) is then placed around the tread portion of the tube, the width and thickness of the strip being such that a desired number of cells of full depth may be formed therein without penetrating or even abutting the last layer of tube rubber.

It has been found that the tough strip of tread rubber (B) should measure in width 00 approximately two thirds of the sectional diameter of the finished tube. To prevent friction between the finished tube and the cover in which it is to be placed the former may have grooves (G) formed therein. The finished tube, when placed in a tire will be thickest at the tread position; and will be of approximately equal thickness at the sides and the base as shown in the drawings.

The built up tube is now placed in a vulcanizing mould provided with means for forming the cells and having an internal cross sectional area equal to that of the cover in which the tube is to be used. At this stage of manufacture the two halves or sections of the mould areclosed. The tube is inflated to a pressure suiiicient to expand the internal air holding portion or cavity D of the tube to the desired sectional area and at the same time force the tread rubber B of the tube against the mould at sufficient pressure to form the air cells (A) in the finished product in well known manner.

The tube before being vulcanized may be further re-inforced by being bound with rubber treated fabric or other suitable material.

If it is desired that the tube G should not be integral with the other portion of the tube, the la ter is made saddle shaped and has tapered flaps at its base between which the tube C containing the air cavity D is inserted as shown in Figure 3.

The outer surface of the cells (A) may be closed by vulcanizing a layer of rubberized fabric or other suitable material over their outer surface. In this latter case the cells (A) may be separately inflated by a hollow needle which is passed through a small unvulcanizable rubber wad in the wall of the cell in well known manner.

Z -17 t v r 1,829,483

If desired'the cell portion of the tube may have incorporated therewith rubberized fabric and the finished product may have beads of well known form for securing it to a rim n he t b. i 'rmi gmcom i a ell vtube capable to Rbeingyused withoutga tire.

I claim: V V I V t l. The process for making a tube for pneumatic --tires, onsisting in' fforming :a' ilam'inatetl-tube o'fsheetsoft air zholding-rubber upon removable'core, expanding=saidftube- I r "by air at a suitable pressure to the fu l l internal diameter of the cover intended'to be 7' used e i h, .epp y ngt e exp d d tube a coating of junction rubber, applying a binding qf sheet rubber ate the so ,formed I tube, placing strips o-ftough' -,tread rubber 1. he b n ng @dj cent zto w epesi i n t "beQeccupied by the tread of the tire, I mould: inguir cellsin tliextreadrubber and Vulcan- I izingthe gbuilt up product While under ,in-

ternalpressure: 1

2., The process fonmakingattube for pneu e 'In atic -;tires, consisting in forming a *lamii nated tubeof she,et soft airtholding rubber upon e rem ovable core; expanding said .tube by :air ,at :a, 7 suitable pressure ,to the liiull in- Iternal diameter of the cover intended to be 7 used therewith, gapp'lying to :the expanded tube a(coating-ofFjunctionrubber, applying a binding ;of ,sheetmubber -;to the so formed tube, placing strips of abrasion resisting material gon the Joindi 1g adjacentto the ,position occupied by the itread of the stireydisr posing stripsogf tough treadrubbernponthe abrasion resisting ,material, .moulding air cells in'the tread @rubber rand vulcanizinggzthe built -up;@pr.oduct while under internal pres'v- I um 7 p I s 6- 3,Thezproeessiormaking ;a tube'ior pneu- 'maticytires, consisting in formingenlamb nsted tube-10fsheetsoitair holding rubber I i. I i

upon a varemcv.able core, expand ngv-said-stube by air, ,at a suitable pressure :to {the full internul diameterofthe cover intended to-be used therewith, applying to the 'eXpunded tube a coating of junction rubber, applying a binding of sheet rubber to thezso formed tube, -placing: strips ofztough itread rubber ion h z i-I di g adiacen h 1POSifiOI10b6 I occupied-by the treadof-the tire,:m0ulding ai-r' c lsendgr oved should rs in thettread r ber and -Vulcanizing {the rbu'ilt up product While iun'der internal pressu e- Y j In testimony whereofI haye hereuntoset my-h nd 7 ERNEsq? HIBBERT,

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